Vehicle electrical systems have evolved over the years from the simplest level, involving a battery and lights, to a more complex level in which the typical passenger vehicle includes a battery, a power distribution center, and an extensive array and assortment of load devices ranging from engine controls, exterior and interior lights, entertainment systems, heating and air-conditioning systems, and many other electronic devices. Often the architecture of the vehicle power distribution and control system is configured to arrange the various load devices, such as those listed above, in groups and control such devices by modules or nodes that are strategically placed in each of several vehicle regions. For example, a modular-based automotive power distribution scheme is disclosed in U.S. patent application Ser. No. 10/055,563 entitled SCALABLE, MODULAR ARCHITECTURE FOR AUTOMOTIVE POWER DISTRIBUTION AND BODY CONTROL FUNCTIONS, filed on Jan. 23, 2002 and assigned to the same assignee as the present invention. Illustrated in FIG. 1 is one such example of a vehicle power distribution system where a vehicle 10 includes one or more power sources 22, such as a battery and alternator, delivering power to a power distribution center 20. Power is then distributed from the power distribution center 20 to various distribution and control nodes, such as, for example, a front passenger node 30, front driver side node 32, left and right body nodes 34 and 36, and a rear node 38. As depicted in FIG. 1, each node connects not only to a power distribution network 60, but also to a control area network 50 that allows one or more vehicle systems to communicate control signals to each node. In this manner, each node can be instructed on how to control the associated group of load devices controlled by that specific node, such as, for example, the group of load devices 42 associated with the front passenger node 30.
Due to various reasons, such as, for example, physical damage, faulty wiring or a faulty connection, it is possible that an unforeseeable power loss can occur to one or more of the power distribution and control nodes of a vehicle, thereby disabling all the load devices associated with the effected nodes. Disablement of certain devices, such as interior lights, radio, locks, and the like (collectively referred to as “class A and B devices”), do not needlessly jeopardize the safe operation of the vehicle. However, devices such as head lights, brake lights, windshield wipers and the like (collectively referred to as “class C devices”) carry out critical functions that contribute to the safe operation of the vehicle. Accordingly, it is desirable that these class C devices remain in operation even after the occurrence of a power fault. Therefore, the inventors of the present invention have recognized the need for a new system and method for distributing power to vehicle devices, via one or more control nodes, that assures power redundancy to certain devices considered critical to the safe operation of the vehicle.